Re: [PATCH v2] mmc: core: Fix error propagation for some ioctl commands

[Ulf Hansson]

On Wed, 13 Sept 2023 at 13:29, Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote:
>
> Userspace has currently no way of checking the internal R1 response error
> bits for some commands. This is a problem for some commands, like RPMB for
> example. Typically, we may detect that the busy completion has successfully
> ended, while in fact the card did not complete the requested operation.
>
> To fix the problem, let's always poll with CMD13 for these commands and
> during the polling, let's also aggregate the R1 response bits. Before
> completing the ioctl request, let's propagate the R1 response bits too.
>
> Reviewed-by: Avri Altman <avri.altman@xxxxxxx>
> Co-developed-by: Christian Loehle <christian.loehle@xxxxxxx>
> Signed-off-by: Christian Loehle <christian.loehle@xxxxxxx>
> Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>

This one is now applied for fixes and has a stable tag added to it.
Please let me know if there is anyone has objections to this.

Kind regards
Uffe


> ---
>
> Changes in v2:
>         - Updated Christian's email.
>         - Updated the commit message.
>         - Initialize mmc_blk_busy_data struct directly.
>
> ---
>  drivers/mmc/core/block.c | 31 ++++++++++++++++++++-----------
>  1 file changed, 20 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
> index b5b414a71e0b..3a8f27c3e310 100644
> --- a/drivers/mmc/core/block.c
> +++ b/drivers/mmc/core/block.c
> @@ -179,6 +179,7 @@ static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq,
>                                struct mmc_queue *mq);
>  static void mmc_blk_hsq_req_done(struct mmc_request *mrq);
>  static int mmc_spi_err_check(struct mmc_card *card);
> +static int mmc_blk_busy_cb(void *cb_data, bool *busy);
>
>  static struct mmc_blk_data *mmc_blk_get(struct gendisk *disk)
>  {
> @@ -470,7 +471,7 @@ static int __mmc_blk_ioctl_cmd(struct mmc_card *card, struct mmc_blk_data *md,
>         struct mmc_data data = {};
>         struct mmc_request mrq = {};
>         struct scatterlist sg;
> -       bool r1b_resp, use_r1b_resp = false;
> +       bool r1b_resp;
>         unsigned int busy_timeout_ms;
>         int err;
>         unsigned int target_part;
> @@ -551,8 +552,7 @@ static int __mmc_blk_ioctl_cmd(struct mmc_card *card, struct mmc_blk_data *md,
>         busy_timeout_ms = idata->ic.cmd_timeout_ms ? : MMC_BLK_TIMEOUT_MS;
>         r1b_resp = (cmd.flags & MMC_RSP_R1B) == MMC_RSP_R1B;
>         if (r1b_resp)
> -               use_r1b_resp = mmc_prepare_busy_cmd(card->host, &cmd,
> -                                                   busy_timeout_ms);
> +               mmc_prepare_busy_cmd(card->host, &cmd, busy_timeout_ms);
>
>         mmc_wait_for_req(card->host, &mrq);
>         memcpy(&idata->ic.response, cmd.resp, sizeof(cmd.resp));
> @@ -605,19 +605,28 @@ static int __mmc_blk_ioctl_cmd(struct mmc_card *card, struct mmc_blk_data *md,
>         if (idata->ic.postsleep_min_us)
>                 usleep_range(idata->ic.postsleep_min_us, idata->ic.postsleep_max_us);
>
> -       /* No need to poll when using HW busy detection. */
> -       if ((card->host->caps & MMC_CAP_WAIT_WHILE_BUSY) && use_r1b_resp)
> -               return 0;
> -
>         if (mmc_host_is_spi(card->host)) {
>                 if (idata->ic.write_flag || r1b_resp || cmd.flags & MMC_RSP_SPI_BUSY)
>                         return mmc_spi_err_check(card);
>                 return err;
>         }
> -       /* Ensure RPMB/R1B command has completed by polling with CMD13. */
> -       if (idata->rpmb || r1b_resp)
> -               err = mmc_poll_for_busy(card, busy_timeout_ms, false,
> -                                       MMC_BUSY_IO);
> +
> +       /*
> +        * Ensure RPMB, writes and R1B responses are completed by polling with
> +        * CMD13. Note that, usually we don't need to poll when using HW busy
> +        * detection, but here it's needed since some commands may indicate the
> +        * error through the R1 status bits.
> +        */
> +       if (idata->rpmb || idata->ic.write_flag || r1b_resp) {
> +               struct mmc_blk_busy_data cb_data = {
> +                       .card = card,
> +               };
> +
> +               err = __mmc_poll_for_busy(card->host, 0, busy_timeout_ms,
> +                                         &mmc_blk_busy_cb, &cb_data);
> +
> +               idata->ic.response[0] = cb_data.status;
> +       }
>
>         return err;
>  }
> --
> 2.34.1
>